The present invention relates to an apparatus and method for use in processing and stacking articles in a continuous stream of discrete individual material pieces. The invention is particularly useful in processing and stacking materials in a high speed material feed stream.
A typical manufacturing or printing process will include a sheet or continuous roll of raw material such as paper or cardboard that enters a press or punch having rotary cutting dies that sever the desired configuration from the sheet and forces the desired configurations out onto a conveyor system for additional processing such as sorting and stacking of the materials in discrete bundles for shipment to customers.
Numerous obstacles exist for processing, organizing and stacking material such as envelopes, documents, folding cartons, etc. especially at high material stream speeds exceeding eight-hundred (800) linear feet per minute. A significant challenge is to manage the linear speed or velocity of the material exiting the rotary dies. For efficiency purposes, the faster the rotary dies can process parts, the more product can be manufactured and shipped in a given period or shift.
Medium speed stacking systems exceeding five-hundred (500) or six-hundred (600) linear feet per minute become too fast for controlled manual or automated separation devices to separate and organize materials into discrete bundles or stacks of material for shipping. Prior art devices including receding pile and water fall stackers have been employed to shingle or overlap the cut or printed materials in the material stream to reduce the linear speed of the material downstream to manageable levels yet maintain a relatively high rotary die speed.
At high speeds, approaching and exceeding one-thousand (1000) linear feet per minute, a significant challenge beyond slowing the material stream velocity is to introduce controlled gaps or separations between discrete quantities of materials so accurate grouping and stacking of the quantities can be achieved. At such speeds, prior art devices such as starwheels, fanwheels and disk devices have been employed. Such devices typically required the materials to be timed from discharge of an upstream device in order for the articles to properly slide into defined regions in the wheel or disk which separate the articles without a need for shingling. Such prior devices suffer disadvantages of complex timing systems, the need to strip or remove the product from the wheel, and require the wheels or other processing devices to be specific to the product size or configuration. These requirements increase the complexity of the systems and significantly reduce adaptability of the devices to accommodate different materials, sizes and configurations. These disadvantages have adversely affected part quality, rate of production and process change-over time.
Prior art devices employing shingled material equally suffered disadvantages of complex mechanical separation devices such as swords and receding pile tables to introduce separations in the shingled stream to organize and sort discrete quantities for bundling and shipping. Such devices were typically complex and were specific to part configuration thereby decreasing efficiency both during production and during process change over to different materials, configurations and sizes.
Consequently, it would be desirable to provide an apparatus and method improving the disadvantageous conditions in the prior processing devices and methods that maintain product quality, are more efficient, less complex and easily adaptable to a change in material size and configuration.
The inventive apparatus includes a shingle wheel having a drum and a control belt defining a path of travel along a portion of the drum. Material in the stream is frictionally engaged between the rotating drum and belt along the path of travel to effectively shingle or overlap the material and reduce the linear velocity of the stream, hereinafter referred to as the shingle path portion or shingle path of travel of the material stream. In a preferred aspect, the control belt rotates relative to the drum and includes a tensioning member that automatically adjusts the tension in the control belt to adjust the radial distance or gap between the drum and belt to accommodate the passage of material along the shingle path of travel.
The invention also includes an apparatus and method for introducing separations between material in the stream and reducing the linear velocity of the stream. In a preferred aspect, a doubler conveyor receives the material stream and includes a pivoting material guide and two diverging conveyors forming two alternate paths of travel for the material in the stream. One of the alternate paths is longer than the other and on convergence of the alternate paths at the outlet end of the doubler conveyor, the diverted materials are placed on top of one another providing controlled separation between successive materials permitting a significant decrease in material stream velocity downstream without compressing the material pieces against one another in the stream.
The invention further includes an apparatus and method for introducing separations between materials in the stream through a discharge conveyor defining a discharge path of travel. In a preferred aspect, the discharge conveyors include two adjacent conveyors having a dam separator coupled to the discharge conveyors that selectively prevents passage of materials relative to the dam and first discharge conveyor. The dam is selectively moveable along the discharge path of travel thereby extending and decreasing the length of adjacent discharge conveyors along the discharge path allowing material to be run out from the second conveyor to introduce a separation without stopping or compressing the material pieces in the continuing stream.